1. Field of the Invention
The present invention relates to novel tetrahydropyridine derivatives with psychotropic activities.
2. Prior Art
Antidopamine agents such as haloperidol (U.S. Pat. No. 3,438,991) are used as an antipsychotic agent. Adverse reactions in the extrapyramidal tract such as delayed dyskinesia are caused by them during long-term therapy. Recently, safer drugs, rimcazole (JP. Pat. Publn. No. 55-64,585) and BMY 148021 (GB Patent No. 2,155, 925), which show high affinity to .sigma. receptors but low affinity to dopamine receptors, have been developed as psychotropic drugs. On the other hand, the exsistence of a binding site of dextromethorphan (DM) in the central nervous system has been reported (J. Musacchio, M. Klein and L. J. Santiago, The Journal of Pharmacology and Therapeutics 247 (2), 424 (1988), High Affinity Dextromethorphan Binding Sites in Guinea Pig Brain; Further Characterization and Allosteric Interactions). DM, which is one of the most popular antitussives, is thought to be effective for ischemic encephalopathy (F. C. Tortella, M. Pellicano and N. G. Bowery, Trips, 10(12), 501 (1989), Dextromethophan and neuromodulation: old drug coughs up new activities). It is also thought that the property of .sigma. receptors, which is labeled with [3H]3PPP adopted in the present invention, resembles that of the DM binding site (J. M. Musacchio, M. Klein and P. D. Cano 11, Life Sciences, 45, 1721 (1989), Dextromethorphan and Sigma Ligands: Common Sites but Diverse Effects).